Diners seem to understand the value of restaurant food. Wine, though, is another matter.

The cook in the house knows the price of boneless chicken breast is, for example, a couple dollars a pound in the store. So, whatever the restaurant charges for a chicken entrée, the home chef can easily calculate the markup.

But what about wine? Does the diner know — or care — about the markup? He doesn't know the wholesale price. And, unless the wine is something he often buys, he has no idea what the retail price is either.

The home cook is hardly going to complain about the markup on the chicken breast because someone else is slaving in the kitchen to prepare it. But diners grumble when they see the price of wine and assess the effort that goes into putting it in the glass. Unlike the chicken breast with a fancy sauce and sides, there is no difference between the same chardonnays bought in different restaurants.

Most wine you buy in a restaurant costs roughly twice as much as in a retail wine store and triple what it cost the restaurant to buy the wine from a wholesaler. Given what goes into putting the wine in a glass, it's hard for a restaurant to justify the markup out of the context of a restaurant's broad financial statement. However, wine and liquor prices often offset losses in the kitchen.

However justifiable, the mystery of wine markups can make for a frustrating experience for a diner facing a wine list of expensive unknowns. Not only does he want to pick a wine that will complement his table's food, but he is looking for a good value — a wine reasonably price that over-delivers in quality.

We are appalled when we see a list of trophy wines that will impress well-heeled collectors but leave nothing but embarrassingly cheap plonk for those who can't shell out more than $50. There are plenty of inexpensive wines — many of them not largely known — that offer decent values even with a 300 percent markup, but either the staff is not knowledgeable or the restaurant doesn't put any emphasis on wine. If that's the case, order a cocktail and call it a night.

Restaurants try to help by offering familiar wines, such as Cakebread Chardonnay. According to the phone app Corkscrew, Cakebread Chardonnay can be found in at least four Annapolis restaurants: O'Leary's Seafood ($88), Sam's on the Waterfront ($72), Tsunami ($75) and Blackwall Hitch ($88). Those restaurants paid $30 for the wine.

Veuve-Clicquot Ponsardin champagne is popular for those celebrating an occasion: Tsunami ($80), Charthouse ($100), Café Normandie ($90) and Severn Inn ($107). But look at the price swing. The wholesale cost of the champagne is $46. Same wine, different markups.

There's a difference between the quality of a $50 steak at Lewnes Steakhouse and a $25 steak at Applebee's. Diners get that. But there is no difference in quality between the same wines sold at two different restaurants.

Wine apps:

If you care about the pricing differences of your favorite wines, check out the phone app, Corkscrew, which provides the prices of restaurant wines in your community.

Raisinable.com provides the average retail price alongside a restaurant's price. But, so far, it includes only the New York market.

Cor.kz gives you access to a database of tasting notes accumulated by wine tasters who are a part of CellarTracker.

Vivino and Delectable offers you information about a wine by snapping a photo of the label.

Of course, using these phone apps on a dinky screen with tired eyes is another matter.

Wine picks:

•Vistalba Corte B 2011 ($30). A complex blend of malbec, bonarda and cabernet sauvignon, this serious wine from the Mendoza region of Argentina has the weight to stand up to grilled meats. Cocoa flavors add to the intrigue of the blackberries.

•Esencia Divina Albarino 2013 ($22). The melon and tangerine notes in this smooth albarino make it a good match with fruit and sauced fish dishes. It has a rich and long finish.

•The Cleaver Red Wine 2013 ($20). If you're planning a backyard barbecue this weekend, you won't find a better match to hamburgers, ribs or pulled pork that this Amador Count blend of zinfandel (70 percent), syrah and petite sirah. Brambly in style, it has juicy blackberry and tobacco flavors.

•E. Guigal Cotes du Rhone Rouge 2010 ($15). If you prefer red wine in even the summer, this is a real gem. A perennial favorite of ours, this delicious blend from the Rhone consists of mostly syrah and grenache. Cherry and dark berry flavors abound in what is deceivingly a big wine for grilled foods.

•Las Rocas Garnacha 2012 ($14). When asked for an inexpensive red wine to pair with grilled meat, we often steer people in the direction of this well-priced Spanish garnacha (grenache in other parts of the world). Bold in style with the acidity you need to pair with food, it has a fruit forward style with dark berry fruit.